Reed relay

ABSTRACT

A reed relay is provided in which the sealed envelope is a tube made of magnetic material instead of glass.

United States Patent Zwobada et al.

REED RELAY Inventors: Rene L. Zwobada, Orsay; Andre Jean Regeffe,Villemomble, both of France International Standard Electric Corporation,New York, N.Y.

Filed: June 19, 1970 Appl. No.: 47,719

Assignee:

Foreign Application Priority Data June 25, 1969 France ..6921308 U.S. Cl..335/l53 Int. Cl. ...H0lh 51/27 Field of Search ..335/15 l-154 PrimaryExaminer-Bernard A. Gilheany Assistant Examiner-R. N. Envall, Jr.

AttorneyC. Cornell Remsen, Jr., Walter J. Baum, Paul W. Hemminger,Charles L. Johnson, Jr., James B. Raden, Delbert P. Warner and Marvin M.Chaban [5 7] ABSTRACT A reed relay is provided in which the sealedenvelope is a tube made of magnetic material instead of glass.

6 Claims, 9 Drawing Figures REED RELAY The present invention relates torelays with contacts encased in a protective tube alsoknown as sealedcontact relays and more commonly known as reed relays.

A description of this type of relay was provided very early in thespecification of French Pat. No. 852,275 filed by the applicant on Mar.28, 1939 under the title: "Electric switching devices." These relays arebasically made up of a glass cylindrical casing, in which are sealed, atboth ends, reeds the outer prolongation of which serve as terminals andthe inner ends of which serve as contacts. The reeds are elastic andmagnetic and their ends are coated with a suitable metal to ensure goodcontact. The airtight casing can contain any inert gas, such as nitrogenor helium. One or several coils around the casing can be energized toclose the contacts.

Apart from their corrosion-resistance properties, these relays areadvantageous in that they operate rapidly. This ac counts for theirwidespread use with digital computers and, in particular, as the maincomponents of speech cross-points in telephone exchanges.

Moreover, in telephone exchanges, power is at a premium. This is whyspeech cross-points which only use power when they change stateshavebeen developed. We are referring to magnetically held sealed contactcross-points like the ones used in the ESSl telephone system (ElectronicSwitching System No. I) installed in the USA. by Western Electric and inthe Artemis automatic switching equipment installed by the applicant anddescribed in the publication Commutation et Electronique" No. 10, Oct.I965, pages 80 to 89. These relays mainly comprise sealed contacts,reversible permanent magnets, which switch the magnetic stream in thecontacts, and energizing coils. They are disadvantageous on the onehand, in that they constitute cumbersome assemblies and, on the otherhand, their assembly is a long and therefore costly process. One aim ofthe invention is to provide for a less cumbersome and less expensiveimproved cross-point than previous ones. For the purpose of thisdescription, the subassembly constituted by the sealed contacts in theircasing will be termed sealed contacts.

According to a feature of the invention, a reed relay comprising anairtight cylindrical casing comprising a remanent magnetic tube withinsulating seals at its ends through which the contact reeds arethreaded and around which the energizing coils are placed is providedfor.

According to another characteristic of the invention, the tube is madeof a ferromagnetic alloy with satisfactory remanent inductionproperties.

Compared with previous known relays, the relay of the invention issmaller, for the thickness of the glass cylinder no longer exists themagnet being located closer to the contact reeds, the gap is smaller.

According to another feature of the invention, the said gap can be madevery small by effecting two constrictions in the magnetic tube and byplacing the seals outside said constrictions so as to achieve therequired electric installation.

Since the magnet is cylindrical, the flux is more concentrated and lessleakage occurs. Therefore for a given contacts attraction field and fora given holding field, the flux of the cylindrical magnet can be weaker,i.e., the number of ampereturns required can be smaller, the number ofcoil turns can be lower thus permitting a reduction in volume of therelay. Finally, as leakage is low, the relays can be placed close to oneanother.

The aims and characteristics of the present invention will become clearfrom the following description of embodiment examples, said descriptionbeing made with reference to the appended drawings in which;

FIG. 1 is a side view, partly in section, showing part of the contactrelay device according to the invention.

FIG. 2 is a side view, partly in section, showing a specific embodimentexample of sealed contact according to the invention.

FIG. 3 is a side view, partly in section, showing components of anotherspecific embodiment example of a sealed contact according to theinvention.

FIG. 4 is a drawing in perspective of specific embodiment example of thesealed contact casing.

FIG. 5 is a side view, partly in section, of a contact relay deviceincorporating the sealed contact of FIG. 2 and two energized coils.

FIG. 6 is a side view, partly in section, of a contact relay deviceincorporating the sealed contact of FIG. Zand four energized coils.

FIG. 7 is a side view, partly in section, of a modification in theimplementation of the sealed contact casing used in the devices in FIGS.5 and 6.

FIG. 8 is a side view, partly in section, of another modification of thesealed casing.

FIG. 9 is a side view, partly in section, of a contact relay deviceaccording to the invention comprising two pairs of identical reedsplaced in a single magnetic cylinder.

The contact relay device shown in FIG. 1 comprises:

a remanent magnetic tube 1 forming a casing and made of ferromagneticalloy of satisfactory remanence for instance steel, with a 0.6 to 0.7carbon content, a 0.5 to 0.8 manganese content and a 0.6 to 0.7 siliconcontent;

two insulating end seals 20 and 2b made for instance of two glass beads;

two reeds 3a and 3b in highly permeable magnetic material which is alsogood electric conductor, said reeds being sealed in Zaand 2b;

an energizing coil 4.

The inside 5 of the casing constituted by 1, 2a and 2b can be filledwith a neutral gas such as nitrogen for example. The outer ends(projecting outside the casing), 60 and 6b, of reeds 3a and 3b formterminals whereas the inner ends, (inside the casing) 7a and 7b, arecoated with suitable precious metal so as to ensure the high resistanceand longlife of the contact.

The device shown in FIG. 1 operates as follows: the contact situatedbetween ends 7a and 7b of reeds 3a and 3b being open, a current is setup in coil 4, said current being such that the magnetomotive forceapplied allows for adequate magnetic induction of tube 1 (saturation);said tube then acquires longitudinal magnetization creating anorth-south magnet the lines of force of which close themselves, inparticular through reeds 3a and 3b and their ends 7a and 7b. Saidendsare mutually attracted, and the contact closes; the current, in coil 4can then be cut, the magnet constituted by tube 1, provided the remanentinduction is sufficient, holds the contact in a closed position. Torelease the relay, i.e., to open the contact, the magnetic field betweenends 7a and 7b of reeds 3a and 3b must be suppressed; as soon as thisfield is suppressed the elasticity causes the reeds to move apart.

A known means consists in feeding a current of decreasing force intocoil 4 thus demagnetizing tube 1. Other embodiment examples which makeit possible to open and close the contact will be described hereafter.

FIG. 2 provides another embodiment example of a sealed contact accordingto the invention in which, in the vicinity of the ends of tube 1, twoconstrictions, 8a and 8b, are made in the said tube. Said constrictionsare designed to reduce the gaps between tube 1 and reeds 3a and 3b; theother components remaining in the same layout as in FIG. 1.

Constrictions 8a and 8b can be made as in 8a for instance, by pinchingtube 1, or as in 8b by adding a ring in the same material as tube 1which is forcibly fitted into said tube.

FIG. 3 shows another embodiment example of a sealed contact in which theends of .tube 1 comprise grooves 9av and 9bv designed to facilitate thelocating of beads 2a and 2b during the sealing process. Naturally theplacing of reeds 3a and 3b in the cylinder can be facilitated if thereed-bead unit is prepared beforehand.

FIG. 4 shows a tube 1 the ends of which have notches 10a and 10b openingoutwards, the notches being diametrically opposite to one another sothat the reed-bead unitsthe beads being round except for a smallprojection on one sidecan be threaded without error into the ends of 1.

FIG. 5 shows a relay device according to 2 in which tube 1 is surroundedby two coils 4a and 4b placed on either side of the sources lla and 11b.As was explained above, the applied magnetomotive force which is the sumof the magnetomotive forces corresponding to sources 11a and 1 lb,causes the magnetic induction of tube 1; said tube becominglongitudinally magnetized thus generating an induction flux along reeds3a and 3b which come into contact.

"The sources of energizing current 11a and 11b can be short pulses,it'suffices that their amplitude be great enough to provide themagnetization power needed to produce suitable remanent inductiomThisinduction is stored in tube 1 and the contact can therefore be closedafter the disappearance of the energizing current pulses and in the sameway be maintained without a holding current being required for either ofcoils 4a and 4b.

The releasing of the relay, i.e., the separation of ends 7a and 7b ofreeds 3a and 3b, can be achieved by suppressing the magnetization oftube l-or at least by diminishing said magnetization considerably; to dothis, coil 4b for example is energized from source llb by a pulse ofcurrent of opposite direction to that which caused, as described above,the closing of the contact, but of a smaller amplitude.

Another process to achieve the resetting of the relay consists inenergizing, as already indicated, coils 4a and 4b from sources 11a and11b by short pulses of current, but in this case with pulses which actin opposition, i.e., pulses of opposite polarities.

It can be assumed that inside tubel, before the application of saidpulses, the magnetic charges are so distributed that the left part ofsaid tube for instance corresponds to a South Pole and,,conversely, thatthe right-hand part of said tube bears opposite charges and correspondsto the North Pole; there is therefore a neutral zone in the center oftube 1 where the charges cancel one another out thus it is as if saidtube comprised two coupled magnets. The magnetomotive force set up bysource 11a is assumed to be sufficient to saturate the mag-' netizationof the left part of tube 1; similarly, the magnetomotive force set up bysource 11b is assumed to be sufficient to saturate the magnetization ofthe right part of tube 1.

The two saturated magnetizations are in opposite directions so that whenenergization via sources 11a and 11b ceases, the two halves of tube 1are characterized by remanent inductions of the same quantity but inopposite directions; in other words the ends of tube 1, bearing magneticcharges of the same sign,

have the same polarity; the resulting induction in reeds 3a, 3b ispractically nil and the reeds move apart.

FIG. 6 shows a relay device comprising a sealed contact, which basicallycorresponds to the one shown in FIG. 2, in

which tube 1 is surrounded by four coils 4a, 4b, 4c and 4d.

higher number, for instance twice as high, as the number of turns ofcoils 4c or 44', characterized by N; turns. Coils 4a and 4d, on the onehand, and coils 4c and 4b, on the other hand, are connected in series.The free ends of the assembly in series of 4a and 4d, emerge on the leftof the device shown in FIG. 6 by prongs 12a and 12d; similarly the freeends of the assembly in series 4c and 4b emerge on the right of thedevice shown in FIG. 6 by prongs 12c and 12b. Ends 6a and 6b of reeds 3aand 3b also serve as prongs.

The three prongs 6a, 12a and 12d, on the one hand, the three prongs 6b,120 and 12b, on the other hand, are held in position using known methodsby rigid insulating parts respectively shown in" schematic form by 13aand 13b: they can be solid with the body of tube 1.

The assembly constituted in this way can then be plugged onto a baseprovided for beforehand and set out, for instance, on printed circuits;prongs 6a, and 12d are plugged onto a first printed circuit, prongs 6b,120 and 12b onto a second printed circuit.

In a modification of the device according to the invention but not shownin the drawing, the outputs of coils 4d and 4b as well as the output ofreed 3b, are extended and brought round the outside of the device intothe proximity of coils 4a and 4c and of output prong 6a of reed 3a; thesix outputs thus placed close to one another are equipped with prongs 6aand 6b corresponding to the contact reeds of prongs 12a and'l2d, cor

responding to coils in series 4a and 4d; and with prongs 12cand 12bcorresponding to coils in series 4c and 4b; these six prongs are held inposition by a single rigid insulating part; the arrangement of theprongs can be such that the operation of plugging onto a base, providedfor prior to assembly, can be performed without any risk of error asregards connecting.

The device shown in FIG. 6 operates as follows: when the coils assembledin series 4a and 4d (or 40 and 4b) are energized from sources 11a (or11b) each coil 4d (or 4c) develops a magnetomotive force E proportionalto N sufficient to saturate tube 1 in a given direction, whereas thecoil associated with an inverted winding-i.e., respectively 4a or4bdevelops a magnetomotive force E proportional to N ,,in the oppositedirectiomE is greater than E for approximately:

A pulse of current applied at one of the assemblies of coils in series4a and 4d for instance-if we imagine that tube .1 is separated into aleft-hand part and a right-hand part on which opposite magnetomotiveforces respectively act, said forces being generated by coils 4a and4dcreates saturated magnetizations of opposite direction on the twoparts of tube 1.

Thus polarities of the same sign stand at the ends of thesaid tube thetwo parts of which are crossedby appreciably equal inductions but inopposite directions: once the pulse has been suppressed, the remanentinductions are also in opposite directions and the total induction whichtravels through reeds 3a and 3b becomes very low. Consequently if ends7a and 7b of said reeds were in contact, they would move apart and ifthey stood apart they would remain so,

When current pulses of the same direction, yielded by sources 11a and11b are simultaneously applied to the two assemblies of coils in series4a-4d and 4c-4b, there stand on the left-hand part and on the right-handpart of tube 1 equal magnetomotive forces proportional to (N -N and ofthe same direction; they have a cumulative effect and it is as if amagnetomotive force E proportional to 2 (N,N acting on the whole of tube1 brought about magnetization saturation with poles of opposite signsappearing at its ends; once the pulse has been suppressed, the remanentinduction flux travelling longitudinally, and in the same direction,through reeds 3aand 3b, causes the ends 7a and 7b which bear oppositesign magnetic charges to move together; the contact closes.

The relay device shown in FIG. 6 can be used to advantages in thematrices of cross-points in centralized control switching systems. Insuch systems, one of the pairs of coils in series 4a-4d for instance, isassembled in series with corresponding coils or the relay constitutingone of the rows of the matrix; the other pair of coils in series 4c-4b,is assembled in series with the corresponding coils of the relaysconstituting one of the columns of the matrix.

In the embodiment examples described heretofore and, in particular inthose illustrated by FIGS. 5 and 6, it was assumed that the devicescould be imagined as being two magnetically independent parts. Now thisis ideally true only, for in practice the induction lines which in thecase of the opening of the contacts emerge in opposite directions fromthe ends of tube 1 (FIG. 5 or 6) are not channeled and are looped viailldefined paths; in some applications if required a magnetic shunt canbe provided which is placed at the center of tube 1, on the outer side,and which reduces the effective air reluctance by shunting the variousmagnetic parts and, consequently reduces the residual induction whichtravels through reeds 3a and 3b (FIG. 5 and 6) thus promoting theopening of the contact.

This magnetic shunt can be advantageously implemented by modifying asshown in FIG. 7 the outside shape of remanent magnetic tube 1; thismodification entails fitting a fairly thin disk 14 of suitable diameterin the middle of the tube. Disk 14 can possibly be equipped with notchesto accommodate the wires of the windings.

Moreover, this magnetic shunt-can be implemented without modifying theshape of the remanent magnetic tube 1, by slipping on the said tubearound its middle, as shown in FIG. 8, a ring component 15 bearing ahighly permeable disk in magnetic material 16.

In some applications of cross-point matrices, several contacts enclosedin a single protective tube are associated and used for a singlecross-point.

FIG. 9 is a schematic diagram of a device according to the inventionwhich, enclosed in a single cylindrical casing l' in remanent magneticmaterial groups two pairs of contact reeds respectively 3'a, 3'b and3"a, 3"b in highly permeable elastic magnetic material which is also agood conductor of electricity.

Reeds 3'0 and 3"a are sealed in insulating member 2a; reeds 3b and 3"bare sealed in insulating member 2b. The ends outside the casing, 6'a and6"a, of reeds 3'a and 3"a operate as terminals whereas their inner ends(i.e., inside the casing), Ta and 7 "a are coated with suitable preciousmetals; similarly, the ends outside the casing, 6'!) and 6"b, of reeds3'b and 3"b operate as terminals whereas the ends inside the easing, 7band 7"b are coated with suitable precious metals.

The section of the cylindrical casing 1 can be circular, elliptical orany other shape according to the specific use to which it is to be put.

Said cylindrical casing can obviously be modified as in the layoutsshown in FIGS. 2, 3, 4, 7 or 8.

Similarly, it is obvious that multiple sealed contacts like those shownin FIG. 9 can be energized using the same methods and the sameassociated energizing coils as the single sealed contacts used in therelay devices already described with reference to FIGS. 5 and 6.

Although the principles of the present invention have been describedhereinabove with a reference to a particular example of embodiment, itwill be clearly understood that the said description has been only madeby way of example and does not limit the scope of the invention.

We claim:

1. A contact relay device encased in a protective tube comprising animpervious cylindrical case, a plurality of contact reeds, means sealingsaid contact reeds through opposite ends of the case to provideextensions outside the case and ends inside the case which operate ascontacts, said reeds being elastic and magnetic, the inner ends of saidreeds including coatings of suitable contact metal, at least oneenergizing coil for said reeds wound around said case, said case beingformed by a tube made of remanent magnetic material, said tube beingclosed at its ends by insulating seals through-which said reeds areextended, and said tube including in the vicinity of each of its ends anairgap formed by a constriction along a certain length of the innerdiameter of said tube.

2. A device according to claim 1, in which the remanent magneticmaterial used for said tube is a ferromagnetic alloy.

3. A device according to claim 1, in which said insulating seals,through which said reeds are extended to close the ends of said tube,are formed by beads of insulating material such as glass, each one ofsaid beads being accommodated at an end of said tube in a volume definedby the inner wall and the constriction in the inner diameter of saidtube.

4. A device according to claim 1, in which said tube has, at each end, anotch on the outside, the notch at one end being diametrically oppositeto the notch at the other end, said notches being used to accommodatesmall projections on corresgaonding insulating sealing parts.

A device according to claim 1, m WhlCIl said tube IS equipped in itsmiddle with a magnetic shunt directed towards the outside and formed ofa projection of said tube shaped like a flat ring.

6. A device according to claim 1, in which said tube has in its middle amagnetic shunt formed by a flat ring of highly permeable magneticmaterial, said ring being adapted to be slid along said tube.

1. A contact relay device encased in a protective tube comprising an impervious cylindrical case, a plurality of contact reeds, means sealing said contact reeds through opposite ends of the case to provide extensions outside the case and ends inside the case which operate as contacts, said reeds being elastic and magnetic, the inner ends of said reeds including coatings of suitable contact metal, at least one energizing coil for said reeds wound around said case, said case being formed by a tube made of remanent magnetic material, said tube being closed at its ends by insulating seals through which said reeds are extended, and said tube including in the vicinity of each of its ends an airgap formed by a constriction along a certain length of the inner diameter of said tube.
 2. A device according to claim 1, in which the remanent magnetic material used for said tube is a ferromagnetic alloy.
 3. A device according to claim 1, in which said insulating seals, through which said reeds are extended to close the ends of said tube, are formed by beads of insulating material such as glass, each one of said beads being accommodated at an end of said tube in a volume defined by the inner wall and the constriction in the inner diameter of said tube.
 4. A device according to claim 1, in which said tube has, at each end, a notch on the outside, the notch at one end being diametrically opposite to the notch at the other end, said notches being used to accommodate small projections on corresponding insulating sealing parts.
 5. A device according to claim 1, in which said tube is equipped in its middle with a magnetic shunt directed towards the outside and formed of a projection of said tube shaped like a flat ring.
 6. A device according to claim 1, in which said tube has in its middle a magnetic shunt formed by a flat ring of highly permeable magnetic material, said ring being adapted to be slid along said tube. 